Endocrinology of ovarian stimulation for in vitro fertilization

Early or late response in poor responders: does it make a difference in cycle outcome?

Ovarian response to stimulation mainly determines the length of stimulation. However, there is no clarity in the literature regarding the optimal duration required to achieve oocyte maturity in patients with the poor ovarian response (POR) defined by Bologna criteria. Therefore, a total of 267 cycles that fulfilled the inclusion criteria were selected retrospectively. Group A constitute of patients with a stimulation period < 9 d (n = 70); and group B included patients with a stimulation period ≥ 9 d (n = 133). The results showed that antral follicle count (5.72 ± 1.82 vs. 5.10 ± 1.78, p = 0.023), serum oestradiol level on hCG day (1286.88 ± 778.18 pg/mL vs. 820.14 ± 479.04 pg/mL, p = 0.001), and total gonadotropin dose used (2949.53 ± 727.92 IU vs 2020.94 ± 415.17 IU, p = 0.0001) were higher in group B when compared to group A. Although the number of total (5.47 ± 3.32 vs 3.86 ± 2.15, p = 0.0001) and mature oocytes retrieved (4.34 ± 2.88 vs 2.84 ± 1.67, p = 0.0001) were higher in group B, no significant difference was observed in the pregnancy rates between groups (25.6 vs 15.7%, p > 0.05). In conclusion, no deleterious effect of a shorter duration of stimulation on cycle outcome was seen in patients with POR.

Reversible cerebral vasoconstriction syndrome associated with hormone therapy for intrauterine insemination

Introduction: Reversible cerebral vasoconstriction syndrome (RCVS) comprises a heterogeneous group of acute neurological diseases which are characterized by thunderclap headache and evidence of reversible multifocal constriction of cerebral arteries. A number of precipitating factors have been described in the literature, including recent childbirth and use of vasoactive substances.

Case description: Here we present the case of a female patient with RCVS which occurred in the setting of hormonal ovarian stimulation for intrauterine insemination.

Discussion: This case possibly contributes to the understanding of the pathophysiological mechanisms underlying reversible cerebral vasoconstriction.

Cerebral blood flow is increased during controlled ovarian stimulation

Estrogen appears to enhance cerebral blood flow (CBF). An association between CBF and physiologically altered hormonal levels due to menstrual cycle, menopause, or exogenous manipulations such as ovariectomy or hormone replacement therapy has been demonstrated. The purpose of this study was to determine the association between ovarian stimulation and CBF in vivo by measuring blood flow in the internal carotid artery (ICA) after pituitary suppression and during controlled ovarian stimulation in women undergoing in vitro fertilization treatment cycles. ICA volume flows were measured by angle-independent dual-beam ultrasound Doppler in 12 women undergoing controlled ovarian stimulation. Measurements were performed after pituitary/ovarian suppression, in the late follicular phase, and at midluteal phase. Blood flow in the ICA increased by 22.2% and 32% in the late follicular and midluteal phases compared with the respective values obtained during ovarian suppression (P < 0.0005 and P < 0.0001, respectively). There was a significant correlation between increments in estrogen levels and increments in CBF when the late follicular phase was compared with the ovarian suppression period (r = 0.8, P < 0.001). Mean blood flow velocity significantly increased (by 15.7% and 16.9%, respectively) and cerebral vascular resistance significantly decreased (by 17.6% and 26.5%) during the late follicular and midluteal phases compared with respective measures during ovarian suppression. There was a significant correlation between an increase in estrogen levels and a decrease in cerebral vascular resistance when the late follicular phase was compared with the ovarian suppression period (r = -0.6, P < 0.05). These changes imply sex hormone-associated intracranial vasodilation leading to increased CBF during controlled ovarian stimulation.

IVF: induction of ovulation in poor responders

All IVF programs have a consistent rate of failure in inducing ovulations. Pharmacological induction of ovulation is otherwise crucial for an IVF program because of the need for more than one ovum. Since it is well known that the best candidates for HMG treatment are hypogonadotropic women a short reversible hypogonadotropic state was induced in IVF patients by LH-RH agonist (Buserelin). Superovulation was then achieved with very high initial doses of FSH (Metrodin) in order to maximize the ovarian response. This technique used in 116 IVF women induced a satisfactory follicle growth even in 70% of the patients already poorly responsive to HMG stimulation.

Primate in vitro fertilization research: preliminary results on the folliculogenic effects of three different ovulatory induction agents on the chacma baboon, Papio ursinus

1. A study was conducted on the chacma baboon, Papio ursinus with three ovulation induction agents in an effort to define a preferential stimulatory protocol with regards to the number and quality of oocytes obtained. 2. Three folliculogenic agents applied in four stimulatory protocol regimens comprised clomiphene citrate in a high (100 mg/day) and low (50 mg/day) dosage, a combination of clomiphene citrate and pregnant mare serum, and human menopausal gonadotropin. 3. A total of 159 oocytes were aspirated by laparotomy from 10 baboon females in 20 induced cycles with an average of 8.0 +/- 5.4 oocytes per aspiration. 4. The highest mean number of oocytes (11.3 +/- 6.7) were obtained with the clomiphene/pregnant mare serum gonadotropin combination. 5. The best fertilization rate was obtained with clomiphene 50 mg. 6. The highest incidence of oocytic cleavage and embryo transfer were achieved with human menopausal gonadotropin (14.8%).

Follicular development: lessons learned from human in vitro fertilization

In vitro fertilization has offered new insights into our understanding of ovulation induction, folliculogenesis, and luteal phase events. This new information is provided by the ability to precisely study these cycles in a frequent and sequential fashion through the use of peripheral blood markers, ultrasound evaluation, and follicular fluid constituents and cell culture techniques, as well as direct observation of the oocyte, fertilization, and cleavage. In these stimulated cycles the follicular phase serum estradiol levels in conjunction with ultrasound were evaluated; a poor correlation was shown between follicle size and number and estrogen production. This distinct dyssynchrony suggests the recruitment of a number of cohorts of follicles in each stimulated cycle. From the biochemical markers in follicular fluid, cyclic adenosine monophosphate has a distinct predictive value in regard to pregnancy in in vitro fertilization-embryo transfer cycles. In the luteal phase, the mass effect of aspiration of great numbers of granulosa cells, the effect of supplemental progesterone, and the influence of high follicular phase estradiol levels remain controversial and, therefore, a less clear cut pattern emerges. Variations in the protocol have not greatly improved the major problems of folliculogenesis associated with ovulation induction and an in vitro fertilization-embryo transfer program, that is, follicular asynchrony and luteal phase deficiency.

In vitro fertilization and embryo transfer program, Department of Obstetrics and Gynecology, University of Adelaide at the Queen Elizabeth Hospital, Woodville, South Australia

A review is presented summarizing the in vitro fertilization experience at the University of Adelaide, Australia. Initial attempts utilizing the normal cycle were unsuccessful in obtaining a pregnancy. Since 1982 the overall ongoing pregnancy rate has been 21% per embryo transfer, 16% per laparoscopy, and 12% per treatment cycle. A detailed description of presently utilized methodology is presented.